The freezing of any free water in the pores of the wood will augment these conditions.
The effect of steaming upon the strength of cross-ties was investigated by the U.S.Forest Service in 1904.

The conclusions were summarized as follows: "(1) The steam at pressure up to 40 pounds applied for 4 hours, or at a pressure of 20 pounds up to 20 hours, increases the weight of ties.

At 40 pounds' pressure applied for 4 hours and at 20 pounds for 5 hours the wood began to be scorched.
"(2) The steamed and saturated wood, when tested immediately after treatment, exhibited weaknesses in proportion to the pressure and duration of steaming.

(See Table XVI.) If allowed to air-dry subsequently the specimens regained the greater part of their strength, provided the pressure and duration had not exceeded those cited under (1).

Subsequent immersion in water of the steamed wood and dried specimens showed that they were weaker than natural wood similarly dried and resoaked."[51] [Footnote 51: Cir.39.Experiments on the strength of treated timber, p.